It is only fitting that English-language readers should have to play catch-up with Danish author Jussi Adler-Olsen's outstanding thrillers featuring detective Carl Morck, who must play catch-up with the culprits of long-forgotten crimes.

Adler-Olsen's masterful storytelling keeps the readers waiting, too, as his teasing, multi-layered plots ever so slowly converge while the reckless, yet fearless, Morck struggles to uncover the truth - without losing his life.

We are now up to book four - three years behind the Danish original - with The Purity of Vengeance (Dutton's American edition), which is published in Britain by Penguin under the title Guilt.

At a black-tie banquet in 1985, a man from Nete Rosen's past confronts her - leading to humiliation, then tragedy, and planting the seed for vengeance.

Fifteen years later, Morck and his Department Q assistants, Assad and Rose, who specialise in cold-case investigations, are dusting off newly delivered old case files when they overhear talk on the police radio about a vicious acid attack on an escort agency owner. It reminds them of the case of Rita Nielsen, a wealthy escort agency owner who had suddenly disappeared in 1987.

Then Morck is handed yet another file, the unsolved killing of a man found floating in a river. The detective knows this case only too well: the man was his uncle, and the young Morck was fishing with him only hours before the killing.

Then a corpse is dug up, which is linked to the brutal gun battle that left Morck with a bullet wound to the head, one colleague dead, and another paralysed.

Can things get any more complicated? Yes they can: Morck and his team discover Nielsen was not the only person to have vanished at the same time. They also uncover shocking evidence pointing to the systematic and brutal treatment of a young woman.

However, their dogged investigation has stirred a powerful - and ruthless - enemy. At once charismatic yet cold-blooded, this foe will stop at nothing - even murder - to ensure dark secrets from the past remain hidden. Morck has unwittingly put his life, and those of his friends and family, in grave danger.

Adler-Olsen expertly cranks up the slow-burn tension as he weaves together the various past-and-present narratives, sprinkling in crafty cliffhangers, witty, well-rounded characterisations and enjoyably bloody action while he leads us, and the indefatigable Morck, to the stunning finale.

Adler-Olsen's four, equally good standalone novels can certainly be enjoyed out of sequence, so fear not. But the experience will be all the richer if you read them in order.

Book five in the series, The Marco Effect, appeared in Danish last year, but … yes, you guessed correctly: you'll have to wait a while to read it in English.